JP 2008-141329 A (see paragraphs 0008-0010 and FIG. 8) discloses a switch device that has a plurality of switch electrodes and a surrounding switch electrode for surrounding the periphery of the switch electrodes. The surrounding switch electrode is equipped with openings that are similar to and slightly larger than each of the switch electrodes, each of the switch electrodes being disposed in each of the openings. The switch device thus configured is set to be turned “on” if a value detected when a finger touches each switch electrode satisfies a predetermined threshold. The surrounding switch electrode is turned on if a dielectric such as water gets in touch therewith. The switch device is configured such that the switch device determines that the switch electrode is operated by the finger if a change in the capacitance of the switch electrode satisfies the threshold and a change in the capacitance of the surrounding switch electrode is not observed, and such that the switch device determines that water or the like is attached to the surrounding switch electrode if changes in the capacitance of both of the switch electrode and the surrounding switch electrode are observed.
A switch device disclosed in JP 2009-111996 A (see paragraphs 0021-0023 and FIG. 1) has a dummy switch as well as a first and second contact switch adjacent to each other. The dummy switch, which is formed in a rectangular and annular shape with missing parts, is provided so as to separately surround the first and second contact switches. Here, assuming both of the contact switches are operated simultaneously if the dummy switch also provides an output simultaneously when the first contact switch provides an output, it is configured to disable the output of the first contact switch. The second contact switch is also operated in the same manner as described above.
The above-described switch device is configured of a transparent electrode material, for example such as ITO (Indium Tin Oxide), and conductive paste such as silver paste is often used to form a wiring pattern thereof. The switch thus configured, which is applied to, for example, an in-vehicle touch panel to be operated, is generally disposed in a place easily viewed.
There remains a continuous need for improved switch devices.